Rupture of pseudoaneurysm of the pancreaticoduodenal arcade after acute aortic dissection in a patient on anticoagulant therapy

Summary

An 81-year-old woman on anticoagulant therapy after mechanical heart valve replacement was admitted because of acute aortic dissection. Anticoagulant therapy had to be continued with heparin even after admission. Gastrointestinal hemorrhage occurred suddenly and she developed hemorrhagic shock. Computed tomography findings suggested that the bleeding was due to rupture of a pseudoaneurysm of the pancreaticoduodenal arcade. After the site of bleeding was identified by angiography, hemorrhage was successfully controlled by embolization with coils. With the aging of the population, vascular complications of arteriosclerosis are likely to increase. This case report provides important insights that could be helpful for treating such patients.

Introduction

With a growing elderly population, the number of patients on anticoagulant therapy after mechanical valve replacement for valvular heart disease is increasing. These patients need to continue anticoagulant therapy even after the development of aortic dissection, but hemorrhage that is difficult to control can occur and may even be fatal. Here we report a patient who had been on oral warfarin potassium therapy since heart valve replacement and developed acute aortic dissection. The gastrointestinal bleeding due to rupture of a pseudoaneurysm of the panrceaticoduodenal arcade was successfully controlled by coil embolization.

Case report

An 81-year-old woman was admitted to our hospital because of chest pain and backache. She had a history of hypertension, hyperlipidemia, and angina pectoris. She had undergone both aortic valve replacement with a mechanical prosthetic valve and graft replacement of the abdominal aorta because of an abdominal aortic aneurysm (AAA) two years earlier. She had no history of pancreatitis. She had suffered from chest and back pain for 4 days before admission. Computed tomography (CT), taken on admission, showed typical Stanford type B aortic dissection, which extended from the origin of the left subclavian artery to the site of anastomosis of the aortic graft inserted to treat AAA. It also revealed a pseudoaneurysm, 2 cm in diameter, located dorsal to the pancreas (Fig. 1). Because the aortic dissection was Stanford type B and her back pain had resolved, it was decided not to operate on but to observe the patient.

Figure 1.

A contrast computed tomography scan on admission. The arrow indicates the compressed celiac artery.

Since the aortic valve replacement, she had been taking warfarin potassium and the international normalized ratio (INR) had been kept to about 2.5. Her vital signs showed no remarkable abnormality. Laboratory tests showed anemia with an Hb of 8.7 g/dL and a C-reactive protein level of 8.7 mg/dL. Oral warfarin potassium was switched to continuous infusion of heparin sodium on the first day of admission. The activated partial thromboplastin time was maintained at 60–80 s. Her aortic dissection did not progress after admission.

On Day 40, a week after resuming warfarin therapy with an INR of 2.59, bloody bowel discharge was detected. She went into shock with a blood pressure of around 70/-mmHg, and was given blood transfusion, fluid infusion, and noradrenaline. Upper gastrointestinal endoscopy revealed pulsating hemorrhage in the third part of the duodenum and distally. However, the endoscope could not reach far enough to identify the bleeding source and perform hemostasis.

CT scans, taken 5 days before hemorrhage, had showed that the pseudoaneurysm had enlarged to 5 cm in diameter (Fig. 2). As immediate hemostasis by a minimally invasive technique was necessary, abdominal angiography was performed (Fig. 3), and the bleeding site was localized to the pancreaticoduodenal arcade. This arcade receives blood from both the celiac artery and the superior mesenteric artery (SMA). Coil embolization was initially performed via the celiac artery, but angiography via SMA still revealed leakage of contrast medium into the duodenum. Coil embolization was then performed via SMA, and hemostasis was achieved (Fig. 4).

Figure 2.

Computed tomography scan obtained on hospital Day 35 (5 days before hemorrhage): the pseudoaneurysm has enlarged to 5 cm in diameter.

Figure 3.

Angiography of the pancreaticoduodenal arcades via the superior mesenteric artery. The celiac artery is compressed by dissection of the abdominal aorta which is indicated by the upper arrow. The lower arrow indicates leakage of contrast medium.

Figure 4.

Post-treatment angiogram showing obliteration of the aneurysm by coil.

A total of 30 units of red blood cells were transfused for hemorrhagic shock. When the patient's condition became stable, oral warfarin therapy was resumed. CT scans, taken after the second embolization, revealed that the aneurysm had disappeared (Fig. 5). There was no recurrence of hemorrhage, and the patient was discharged.

Figure 5.

Computed tomography scan obtained after coil embolization: the aneurysm has disappeared.

Discussion

There have been many reports of gastrointestinal hemorrhage during treatment with warfarin potassium [1], [2], [3], [4]. In patients on anticoagulant therapy after mechanical valve replacement, anticoagulant therapy cannot be discontinued even if aortic dissection occurs and bleeding may have a very serious outcome. White et al. reviewed 3865 patients on warfarin sodium therapy and reported that there were 0.83 life-threatening hemorrhagic events per 100 patients annually, and that hemorrhage recurred in 56% of the patients who continued to receive anticoagulant therapy [5].

Aneurysms rarely arise from the pancreaticoduodenal arcades and hemostasis is difficult to achieve if rupture occurs, leading to a high likelihood of a fatal outcome [6]. Pancreaticoduodenal pseudoaneurysm develops secondary to local injury, such as abdominal trauma and septic emboli [7], or in association with acute or chronic pancreatitis [8]. Although there have been a few case reports, rupture of pancreaticoduodenal pseudoaneurysm is very rare and its frequency is unknown [7], [9]. In the present patient, bleeding was thought to have occurred from the pancreaticoduodenal arcade. The cause of the pseudoaneurysm was not certain, and progression of aortic dissection and stenosis of the celiac artery might be a possible cause.

When rupture occurs, treatment should be performed by surgery or coil embolization. Ducasse et al. reported that the survival rate achieved by coil embolization was the same as that by surgery, while its complications were less common than those of surgery [10].

When hemorrhage develops in patients on oral warfarin therapy, it is important to identify the source of bleeding as soon as possible because the outcome can be fatal. In this case, we performed gastro-intestinal fiberscopy. But the endoscope could not reach far enough to identify the bleeding source.

We took an angiographic procedure, because we can diagnose and perform embolization at the same time. Serial CT scan is important to decide the strategy for diagnosis and treatment. Our patient had aortic dissection and performing surgical hemostasis was considered almost impossible. Therefore we had to perform catheterization although it was considered a rather high-risk procedure. Angiography identified the bleeding site and hemostasis was performed successfully. With the aging of the population, vascular complications of arteriosclerosis are likely to increase in the future. This case report provides information that could be helpful for treating similar patients.

Conclusions

Rupture of pseudoaneurysm of the pancreaticoduodenal arcade after acute aortic dissection in a patient on anticoagulant therapy was successfully treated by coil embolization. Targeted catheter intervention in combination with CT scans in a patient with vascular complications is a useful strategy for treatment of complicated vascular events.